Dr. Strath's past and current research focus has been on physical activity (PA) assessment and PA and health indices. His immediate goal is to acquire new professional skills to help him achieve a long-term goal of developing a successful independent extramurally-funded research program in PA and health for the elderly. The outlined K01 Career Development Award (CDA) should provide Dr. Strath with the required training to achieve his long-term goal. Dr. Strath's research CDA consists of acquiring new skills associated with and complimentary to his proposed research plan, which consists of: a) structured activities including formal course work;b) attendance and presentations at scientific meetings and journal clubs;and c) regular interactions with his sponsors and mentoring team. The immediate environment for Dr. Strath's proposed training and research plan should be excellent. The sponsors and mentoring team identified are exceptionally qualified to provide the necessary mentoring and have dedicated a substantial time commitment to helping Dr. Strath succeed in his professional goals. The general aim of studies 1 and 2 will seek to refine objective PA assessment methods specific to the elderly. Experimentally, this will consist of establishing criterion related validity during standarized activities, and different lifestyle related activities, producing age appropriate equations to regress objective monitoring to measured PA. Reliability and construct validity will be further established. These studies are necessary to obtain accurate PA outcomes associated with study 3. The general aim of study 3 is to determine the relative effectiveness of individually- tailored, mail mediated, interventions designed to increase PA and health and well-being in the elderly. Experimental design will consist of a delayed-control arm and three experimental interventions. Intervention 1: continuous pedometer feedback;Intervention 2: motivationally-matched mailed feedback;and Intervention 3: the interaction of intervention 1 and intervention 2. New innovative information arising from this experimental design is that it will permit an evaluation of continuous pedometer feedback, the usefulness of individually-tailored, mail mediated interventions, and the combined effects of both. This intervention design is both novel and innovative in the elderly.